JP4731802B2 - Process for the production of phenol by hydrodeoxylation of benzene-diols - Google Patents

Description

  The present invention relates to a process for the production of phenol by catalytic hydrodeoxygenation of benzene-diols.

  More particularly, the invention relates to a process for the continuous production of phenol by hydrodeoxylation of benzene-diols with hydrogen, carried out in aqueous solution in the presence of a catalyst based on elements of group VIB or VIII of the periodic table. About.

  Phenol is a very important industrial intermediate used, for example, in the production of polycarbonates or other phenolic resins.

  Low cost benzene-diols are available as natural source derivatives or by-products of industrial chemical processing.

  Hydrodeoxylation reactions are well known to those skilled in the art (see, for example, E. Furimsky, CATAL. REV.-SCI. ENG., 25 (3), 421-458 (1983)). .

  Furimsky describes hydrodeoxylation, in particular the synthesis of products published in the field of reactions carried out on raw materials used for the production of liquid fuels or model compounds.

  Since the presence of oxygen in these liquid fuels is undesirable, the hydrodeoxylation reaction is actually applied mainly to the processing of raw materials for the production of fuels for the purpose of complete and thorough deoxygenation of reagent substrates. These raw materials contain a considerable amount of oxygen, usually due to the presence of hydroxyl, carbonyl, carboxyl, ether, ketone groups and the like. Among the most widely studied raw materials, liquids derived from liquefaction of carbon are cited (page 434), where the oxygen content is mainly based on the presence of phenol groups.

  Among the model compounds used to study the hydrodeoxylation reaction, o- and p-cresol, naphthol, phenol, o-phenylphenol and other phenols are listed (Table 5, page 442).

  Due to their structure, phenols may require the presence of a catalyst in addition to the presence of a reducing agent for complete deoxylation (Table 2, page 429).

  Although the hydrodeoxylation reaction can be carried out in the presence of many catalysts, it has often proved more effective to contain Mo or W in combination with Ni or Co as a promoter; phenol type In the case of these compounds, catalysts based on Th and Pt oxides have also proved useful (page 444).

  One of the disadvantages observed in the hydrodeoxylation reaction is the deactivation of the catalyst due to the presence of water formed during the reaction (page 455).

E. Furimsky, CATAL.REV.-SCI.ENG., 25 (3), 421-458 (1983)

Summary of the Invention

  High conversion, selectivity and production even when operated in aqueous solution, based on partial and selective hydrodeoxylation reactions carried out with hydrogen in the presence of catalysts based on elements of group VIB or VIII of the periodic table A process has now been found that can convert benzene-diols to phenol at a high rate.

  This is a surprising result given previous knowledge that water was identified as the causative agent that inhibits the catalyst in the hydrodeoxylation reaction.

  Furthermore, in the reaction in which the substrate to be deoxygenated consists of benzene-diols, the use of water as a solvent has many advantages from both a technical and economic point of view. Water can actually keep both reagents and products at high concentrations in solution. Furthermore, water is completely inert to reagents and products in the reaction environment. As a reaction solvent, water also has an advantage that it has a high heat capacity and, in turn, has the property of suppressing the temperature rise due to the enthalpy of the deoxylation reaction. Finally, water is exceptionally cheap.

  In its broadest aspect, the present invention relates to a catalyst based on a temperature of 250 to 500 ° C., a pressure of 1 to 100 bar, and a group VIB element or a mixture thereof or a group VIII element or a mixture thereof. The present invention relates to a method for producing phenol, characterized in that phenol is obtained by hydrodeoxylation of benzene-diols with hydrogen in an aqueous solution in the presence of

  When operated according to the method of the present invention, 1,2-benzenediol (catechol, hereinafter abbreviated as 1,2-BD), 1,3-benzenediol (resorcinol, hereinafter 1,3-BD), 1,4- It is possible to convert benzenediol (hydroquinone, hereinafter 1,4-BD) and mixtures thereof to phenol with high efficiency and selectivity.

Detailed description of the invention

The reaction is carried out at a temperature of 250 to 500 ° C., preferably 300 to 450 ° C., a pressure of ^{1 to} 100 bar, preferably 3 to 50 bar, and a space velocity of 0.1 to 10 h ⁻¹ , preferably 0.5 to 5 h ⁻¹ . (WHSV = Weight Hourly Space Velocity, expressed as benzene-diols kg / h / catalyst kg).

  In particular, the reactor feed is a solution of benzene-diols in water at a concentration of 5-60% by weight, preferably 10-40% by weight, and a molar ratio to the benzene-diols of 2-50, preferably 5-50%. It consists of 30 hydrogens.

  The catalyst may be selected from those for hydrodeoxylation based on elements of group VIB or VIII of the periodic table.

  When the catalyst is based on a Group VIB element, it can contain elements belonging to Group VIII and phosphorus as promoters. Group VIB elements can be used in a mixture, of which molybdenum and tungsten are preferred. Of the Group VIII promoters, nickel, cobalt, iron and ruthenium are preferred and may be used in combination with each other and with phosphorus.

  When the catalyst is based on a Group VIII element, it can contain zinc, rhenium, selenium, tin, germanium and lead as promoters. Group VIII elements can be used in a mixture, among which cobalt, palladium, nickel and platinum are preferred. Accelerators may be mixed with each other.

The active phase is preferably supported on a carrier. Preferred carriers are inorganic oxides such as alumina, silica, titanium dioxide, crystalline or amorphous aluminosilicate, crystalline spinel having the general formula F ²⁺ R ₂ ³⁺ O ₄ (F ²⁺ includes Mg, Fe, Zn, Mn, Ni, etc. R ³⁺ includes Al, Fe, Cr, etc.) or a mixture thereof. The typical surface area of these materials is 1 to 800 m ² / g, preferably 10 to 500 m ² / g, and the pore volume is 0.05 to ² cm ³ / g, preferably 0.1 to 1.5 cm ³ / g. is there. The catalyst and carrier may take a form suitable for use, for example in a fixed bed reactor, extrudates, tablets, spheres of 1-12 mm size are suitable for the purpose.

  In the case of catalysts based on Group VIB elements, the elements are usually present on the carrier in a concentration of 1 to 50% by weight, preferably 3 to 30% by weight. These catalyst promoters are usually present in a concentration of 0.1 to 100 atomic%, preferably 1 to 50%, relative to the elements of group VIB. Examples of these catalysts are Mo, W, CoMo, NiMo, NiW, FeMo, RuMo, CoMoP, NiMoP, CoWMo, CoWMoP, provided that they do not impose any restrictions on the possible composition or indicate any preference.

Prior to being used in the reaction, these catalysts are subjected to treatments to alter their chemical properties, such as H ₂ S, dimethyl sulfide, dimethyl disulfide, carbon sulfide or sulfidation with other compounds useful for the purpose. You may attach.

  In the case of catalysts based on Group VIII elements, the elements are usually present on the carrier in a concentration of 0.05 to 20% by weight, preferably 0.1 to 10% by weight. These catalyst promoters are usually present at a concentration of 0.5 to 200 atomic percent, preferably 1 to 120 percent, relative to Group VIII elements. Examples of these catalysts are Pt, Pd, Co, Ni, PtZn, PtRe, PtNi, PtSe, PtSn, PtGe, PdPb, PdSn, without any limitation on the possible composition or showing any preference. is there.

  The subject catalysts of the present invention can be prepared by incipient wetness techniques or absorption from solution.

  The former method consists of impregnating the porous carrier with a volume of solution containing a soluble precursor of the active phase equal to the pore volume of the carrier used. Thus, the precursor present in the solution is quantitatively absorbed by the carrier. To reach the desired element loading, the operation is repeated several times, alternating with it and drying.

  In the second method, starting from a solution in which the carrier is dispersed, the active phase precursor is absorbed into the carrier.

  Among the precursors that can be used, commercial solutions of ammonium heptamolybdate tetrahydrate, cobalt nitrate hexahydrate, nickel nitrate hexahydrate, iron nitrate nonahydrate, ruthenium chloride, hexachloroplatinic acid (Pt7. 7%), according to what is disclosed in the current state of the art.

  The impregnated carrier may be subjected to chemical treatment, and in some cases, alternately with heat treatment. A typical chemical treatment is, for example, reduction of a carrier impregnated with hexachloroplatinic acid with a solution of sodium formate at 85-95 ° C.

  Production always ends with final heat treatment.

  In an embodiment of the invention, the reaction is carried out in an adiabatic fixed bed reactor containing a catalyst as described above, wherein the ratio between total moles of hydrogen and benzene-diols is 2: 1 to 50: 1. A stream containing an aqueous solution of benzene-diols at a concentration of 5 to 60% by weight is fed with the hydrogen stream in such an amount as follows. The feed is vaporized and heated to a temperature of 250-500 ° C. and the pressure is kept at 1-100 bar. The stream exiting the reactor consists of residual benzene-diols, phenol formed in an aqueous solution, and residual hydrogen to be recycled.

  In another aspect of the invention, the temperature is increased in each reactor, for example by maintaining it below 40 ° C., in order to cool the stream exiting one of the reactors before being introduced into the next. The reaction is carried out continuously in two or more adiabatic fixed bed reactors. In this embodiment, both the water feed and the hydrogen feed can be fed separately to a single reactor. A fractional feed is particularly useful because it avoids the use of an intermediate exchanger for cooling. Two reactors are usually sufficient to keep the temperature rise of a single reactor within the desired value.

  By operating so that the temperature rise in each reactor does not exceed 40 ° C., a high selectivity to phenol is obtained.

  FIG. 1 schematically shows an apparatus suitable for the process aspect of the plant configuration described above.

  With the catalyst and the most appropriate operating conditions, the reactor can be operated for hundreds of hours with 100% conversion of benzene-diols and> 95% phenol selectivity.

  By extending the reactor run time, the conversion rate tends to decrease, but the selectivity remains very high. In order to maintain the desired degree of conversion, the reaction temperature can be gradually increased within the range of 250-500 ° C.

  The cause of the decrease in activity is carbonaceous deposit on the catalyst in use in the reaction.

  The catalyst which can be used for the purposes of the present invention is based on what is known in the state of the art for recovering the initial activity and for the removal of the deposits by combustion, without any special problems. It was observed that it could be subjected to manual regeneration.

The regeneration process can be performed in the same reactor to which a catalyst has been added for the reaction. Regeneration is a mixture of oxygen and nitrogen in a ratio of 0.1-20% by volume, and space velocity (GHSV = Gas Hourly Space Velocity, expressed as gas mixture L / h / catalyst L) = 3000 ÷ 6000 h ⁻¹ Is usually carried out at a temperature of 400 to 550 ° C. and a pressure of 1 to 3 bar.

  In the case of a continuous process embodiment, it is preferred to have two reaction systems that are alternately subjected to reaction and regeneration.

  The process according to the invention increases the overall yield to phenol in a process for the direct synthesis of phenol from benzene with hydrogen peroxide, a process leading to the formation of significant amounts of benzene-diols (US06133487 and Italian patent MI2001A002410). Can be used conveniently.

  Some illustrative examples are presented for a better understanding of the invention and for its embodiments, however, they should not be considered as limiting the scope of the invention itself.

Catalyst production example
Example 1
Mo / Al ₂ O ₃ type catalytic alumina (Alumina Spheres 1.0 / 160 Condea-Sasol, diameter = 1 mm, pore volume = 0.45 ml / g minimum, surface area = 150-170 m ² / g) 50 g is dried overnight at 120 ° C. Let They are then impregnated with a solution of 3.45 g of ammonium heptamolybdate dissolved in 23 g of demineralized water at room temperature by incipient wetness techniques. After aging for about 2 hours, the sample is dried at 140 ° C. for 3 hours. Two more impregnation / drying cycles are repeated and the sample is then calcined at 500 ° C. for 8 hours. The calculated molybdenum content is Mo = 9.6% by weight based on the production method.

Example 2
A procedure similar to that described in W / Al ₂ O ₃ type catalyst example 1 is employed, except that 1.04 g of ammonium (para) tungstate dissolved in 26 g of demineralized water instead of the molybdenum-containing solution. Using the solution, the aging time is 1 hour instead of 2 hours, and another impregnation / drying cycle is performed only once rather than twice. The calculated tungsten content is W = 2.9% by weight.

Example 3
An operation similar to that described in Example 1 of HPA / Al ₂ O ₃ type catalyst is employed, except that phosphotungstic acid (Acros, H ₃ PO ₄₀₎ dissolved in 26 g of demineralized water instead of the molybdenum-containing solution. ^{_{W 12 * xH 2 O, MW}} = 2880.17, WO 3 82% minimum, 800 ° C. for maximum weight loss rate = 17%) with a solution of 1.70 g, the aging time is 1 hour instead of 2 hours. The calculated tungsten and phosphorus contents are W = 6.2 wt% and P = 0.08 wt% based on the manufacturing method.

Example 4
A CoMo / Al ₂ O ₃ type catalyst was prepared in the same manner as in Example 1 except that the impregnating solution was prepared using 3.45 g of ammonium heptamolybdate and 2.67 g of cobalt nitrate hexahydrate. The calculated cobalt and molybdenum contents are Co = 2.7 wt% and Mo = 9.3 wt% based on the production method.

Example 5
CoMoW / Al ₂ O ₃ type catalyst The same production procedure is used as in the case of the catalyst of Example 4, except that two further impregnations are finally dried with a solution of 25 ml of demineralized water and 1.04 g of ammonium (para) tungstate. It is carried out with a non-calcined catalyst, with a 3 hour drying at 140 ° C. in between. The solid is dried at 140 ° C. for 3 hours and then calcined at 500 ° C. for 8 hours. The calculated cobalt, molybdenum and tungsten contents are Co = 2.6% by weight, Mo = 9.0% by weight and W = 2.4% by weight based on the production method.

Example 6
50 g of FeMo / Al ₂ O ₃ type catalytic alumina (Alumina Spheres 1.0 / 160 Condea-Sasol) is dried at 120 ° C. overnight. They are then impregnated with a solution of 3.79 g of iron nitrate nonahydrate dissolved in 27 g of demineralized water at room temperature by incipient wetness techniques. After aging for about 1 hour, the sample is dried at 140 ° C. for 3 hours. The impregnation is then carried out with a solution consisting of 3.45 g of ammonium heptamolybdate and 27 g of demineralized water and the sample is dried at 140 ° C. for 3 hours. Two more Fe impregnation / drying-Mo impregnation / drying cycles are repeated and the sample is then calcined at 500 ° C. for 8 hours. The calculated iron and molybdenum contents are Fe = 2.5 wt% and Mo = 9.3 wt% based on the production method.

Example 7
A procedure similar to that described in Co / Al ₂ O ₃ type catalyst example 1 was employed, except that the impregnation solution was prepared using 2.67 g of cobalt nitrate hexahydrate. The calculated cobalt content is Co = 3.1% by weight based on the production method.

Example 8
50 g of Pt / Al ₂ O ₃ type catalytic alumina (Alumina Spheres 1.0 / 160 Condea-Sasol) is immersed in 200 ml of demineralized water for 16 hours. After draining and washing twice with about 100 ml of water each, the alumina is suspended in 80 ml of an aqueous solution containing 3.2 g of hexachloroplatinic acid solution (Pt = 7.696%) in a rotary evaporator flask. The mixture is slowly rotated at 30 ° C. for 2.5 hours and then a solution consisting of 1.0 g of sodium formate dissolved in 50 g of demineralized water is added. Again in the slowly rotating rotary evaporator flask, the solution is heated to 85 ° C. for 90 minutes, drained, filtered and washed with about 5 L of water at 60 ° C. Drain it and dry at 120 ° C. for 18 hours. The platinum content calculated for the catalyst is Pt = 0.5% by weight, based on the production method.

Example 9
Preparation of spinel used as carrier 1500 ml of demineralized water adjusted to pH 10 with ammonium hydroxide (32% Carlo Erba) is poured into 5 L glass. A second solution consisting of 203.3 g magnesium chloride and 482.86 g ammonium chloride hexahydrate, made up to 2 L with demineralized water, is slowly added to the ammonia solution with stirring. During the mixing of the solution, the pH is kept at a value of about 10 by addition of a suitable solution of ammonium hydroxide. After the addition is complete, the mixture is kept under stirring for 2 hours and the solid is aged in the mother liquor for 16 hours, filtered, washed with wash water until neutral pH and dried at 120 ° C. for 16 hours. The solid is calcined at 400 ° C. for 16 hours and then at 600 ° C. for an additional 16 hours. The resulting oxide is crushed and sieved through 18-35 mesh.

1. 1 ml of a solution of ZnCl ₂ in water (prepared by dissolving 2.2 g of zinc chloride in 50 ml of demineralized water) and 5 ml of catalyst chloroplatinic acid solution (Pt = 2 mg / ml) of PtZn and MgAl type spinel . 10 g of solid material is impregnated with a solution of 5 ml. The impregnated solid is aged at room temperature for 16 hours, dried at 120 ° C. for 16 hours, and calcined at 500 ° C. for 16 hours. The calculated platinum and zinc contents are Pt = 0.1 wt% and Zn = 0.2 wt% based on the production method.

Commercially available catalysts For the purposes of the present invention, catalysts that are commercially available in fields different from those of the present invention can be used.

For example, based on cobalt-molybdenum-phosphorus and nickel-molybdenum-phosphorus, each supported on alumina, described in the technical and commercial literature by the manufacturer (Engelhard Italiana SpA-Via Siusi 20-20132 Milan-Italy) Engelhard ESCAT ^™ H-60 and ESCAT ^™ H-50 can be used.

  For example, Akzo Nobel KF-756, a catalyst based on cobalt-molybdenum and nickel-molybdenum, respectively, described in the technical and commercial literature by the manufacturer (Akzo Nobel Chemicals SpA-Via E. Vismara 80-20020 Arese MI-Italy) And KF-841 can also be used.

The catalytic activity test described in the example of catalyst performance was carried out in an experimental apparatus, where it is possible to investigate the operating conditions that can be adopted for optimal operation of the process. The apparatus and operating procedure are described below.

Catalyst Test: Equipment and Operating Procedure Hydrodeoxylation reaction of benzene-diols, the following features: Material = AISI 316L stainless steel, length 180 mm, inner diameter (φ _int ) = 11.5 mm, outer diameter (φ _ext ) = It is carried out in the vapor phase in a tubular fixed bed microreactor with a 3 mm thermocouple sheath. The reactor is placed in an oven that can be set to the temperature selected for the reaction.

  The catalyst used in the test has a size of <2 mm; when using a commercial catalyst produced in industrial size, it is pre-milled to the desired dimensions. The catalyst added is 5.0 g which is placed in the reactor between two layers of granular quartz.

  The solution of benzene-diols is preheated and then added to the top of the reactor, which is then vaporized and mixed directly with hydrogen in the reactor (in the layer of granular quartz) before contacting the catalyst. The liquid feed solution is charged with an HPLC type pump, and the hydrogen flow rate is adjusted with a mass flow rate controller.

  The plant pressure is controlled by a regulating valve located at the reactor outlet.

  In the activation phase of the activity test, the catalyst is heated to the reaction temperature in a hydrogen stream at the pressure and flow rate specified for the test and maintained under these conditions for 1 hour. Water is then fed, and after 30 minutes, the actual catalyst test begins with the start of feeding the aqueous solution of benzene-diols.

  The effluent vapor mixture from the pressure control valve is condensed and a sample of the reaction crude product is collected to assess catalyst performance.

  Samples are analyzed by gas chromatography to evaluate catalyst performance by calculating benzene-diols conversion and phenol selectivity.

The regeneration of the catalyst after the activity test was carried out in the same reactor as that used for the reaction. The operating conditions are as follows: temperature = 450-550 ° C., pressure = 1-3 bar, oxygen concentration = 0.1-20% and GHSV space velocity = 3000 ÷ 6000 h ⁻¹ . In particular, the process begins with only a nitrogen stream, to which the same stream of air is gradually added (in about 1 hour). The nitrogen stream is then gradually reduced until it eventually disappears (in about 1 hour) and the process is continued for 5-10 hours. At the end of the treatment, the reactor may be flushed with a nitrogen stream and the catalytic activity test resumed.

  The table below shows examples of catalytic activity for catalysts based on Group VIB elements of the periodic table (Examples 10-23) and Group VIII elements of the Periodic Table (Examples 24-27). Abbreviations and symbols are used in the table, the meanings of which are given below.

Abbreviations and symbols used in the examples 1,2-BD = 1,2-benzenediol 1,4-BD = 1,4-benzenediol BD = benzene-diols α = of supplied benzene-diols WHSV
β = operation time from the start of the catalyst test, time in stream Y = operation time from the last regeneration performed in the reactor, time in stream δ = 1, conversion rate for the sum of 1,2-BD + 1,4-BD ε = selectivity for all transformed BDs

FIG. 2 is a schematic diagram of an apparatus for hydrodeoxylation of benzene-diols by two steps.

Explanation of symbols

R1 First reactor R2 Second reactor C Condenser S Gas-liquid separator 1 Benzene-ols in aqueous solution, supplied to R1 2 Hydrogen supplied to R1 2 ′ Fresh hydrogen, supplied to R1 2 ”Recycled hydrogen, supplied to R1 3 Stream 1 exiting R1 Cooling water 5 Cooling mixture, supply to R2 6 Recycled hydrogen, supply to R2 7 Stream exiting R2 8 Aqueous solution of unpurified phenol 9 Hydrogen for recycling

Claims (22)

Benzene in aqueous solution in a continuous operation in the presence of a catalyst comprising a temperature of 250-500 ° C., a pressure of 1-100 bar, and a group VIB element or mixtures thereof or a group VIII element or mixtures thereof of the periodic table -; and obtaining phenol by hydro deoxygenation by hydrogen Jio Le method of phenol. Benzene - Jio Le is 1,2-benzenediol, 1,3-benzenediol, is selected from 1,4-benzene diol, or mixtures thereof, The method of claim 1. Reaction temperature of 300 to 450 ° C., a pressure of 3～50Bar, and benzene - at a space velocity of 0.1 to 10 ^-1, expressed as kg of Jio Le of kg / h / catalyst, carried out in the vapor phase The method according to claim 1 or 2. The process according to claim 3, wherein the reaction is carried out at a space velocity of 0.5 to 5 h- ¹ . The reaction is carried out in an adiabatic fixed bed reactor containing a catalyst, in which hydrogen is added in an amount such that the molar ratio of hydrogen to benzene-diol (H ₂ / BD ratio) is 2-50. together with the flow, benzene - Jio Le stream containing a concentration of 5 to 60% by weight aqueous solution of is supplied, the method according to any one of claims 1-4. Benzene hydrogen - in an amount such that the molar ratio diol _(H 2 / BD ratio) of 5 to 30, together with the hydrogen stream, benzene - concentration 10 to 40% by weight aqueous solution of Jio Le is in the reactor The method of claim 5, wherein 7. A process according to claim 5 or 6, wherein the feed stream is vaporized and heated to a temperature of 250-500 [deg.] C. and the pressure is kept at a value of 1-100 bar. The process according to claim 1, wherein the catalyst comprising a Group VIB element contains an element selected from molybdenum and tungsten. The process according to claim 1, wherein the catalyst comprising a group VIB element contains , as a promoter, an element selected from elements belonging to group VIII, phosphorus or mixtures thereof. The process according to claim 9, wherein the Group VIII promoter contains an element selected from nickel, cobalt, iron and ruthenium. The process according to claim 1, wherein the catalyst comprising a Group VIII element contains an element selected from cobalt, palladium, nickel and platinum. The process according to claim 1, wherein the catalyst comprising a Group VIII element contains , as a promoter, an element selected from zinc, rhenium, selenium, tin, germanium and lead or mixtures thereof. 13. A process according to claim 9 or 12, wherein the catalyst is supported on a support selected from alumina, silica, titanium dioxide, crystalline or amorphous aluminosilicate, crystalline spinel or mixtures thereof . Present in a catalyst comprising a Group VIB element on the carrier at a concentration of 1 to 50 wt%, accelerator of the catalyst is present in a concentration of 0.1 to 100 atomic% with respect to the element of group VIB, claim 13. The method according to 1. Present in a catalyst comprising a Group VIB elements on the carrier in a concentration of 3-30 wt%, accelerator of the catalyst is present at a concentration of 1 to 50 atomic% with respect to the element of group VIB, in claim 14 The method described. The catalyst containing an element of group VIII is present on the support at a concentration of 0.05 to 20 wt%, accelerator of the catalyst is present in a concentration of 0.5 to 200 atomic% with respect to the element of group VIII, The method of claim 13 . Present on the support at a concentration catalyst of 0.1 to 10 wt% including elements of Group VIII, promoter of the catalyst is present at a concentration of 1 to 120 atomic% with respect to the element of group VIII, claim 16. The method according to 16 . The reaction is carried out continuously in two or more adiabatic fixed bed reactors, and the reaction is conducted with a stream exiting one reactor in order to suppress the temperature rise in each reactor to 40 ° C. or less. The process according to claim 1, which is carried out by cooling before entering the next reactor. The reaction is carried out by supplying water and hydrogen to the two or more adiabatic fixed bed reactors, and both the supplied water and the supplied hydrogen are fed separately to each single reactor and the temperature in each reactor. The process according to claim 18 , wherein the operation is carried out such that the rise does not exceed 40 ° C. 19. The method of claim 18 , wherein the reaction is performed by alternately subjecting to reaction and regeneration using two reactors alternately . Includes a reproduction said method of the catalyst, regeneration of the catalyst, the catalyst, expressed as a mixture of oxygen and nitrogen in the 0.1 to 20 volume% oxygen concentration ratio, and gas mixture of L / h / catalyst L 3000 ÷ the space velocity of 6000h ^-1, performed by Succoth biasing the regeneration by combustion at a pressure of temperature and 1~3bar of 400 to 550 ° C., the method of claim 1 that. Reproduction, the catalyst is carried out in the reactor and the same reactor placed for reaction, a method according to claim 21.

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